Combustible primer plug



y 1967 J. B. QUINLAN ET AL 3,320,887

COMBUSTIBLE PR IMER PLUG Filed Aug. 5, 1965 JOSEPH B. QUINLAN JOHN J.SCANLON JR,

United Sttes ABSTRACT OF THE DISCLOSURE A primer plug, for use in therearward portion of a round of caseless ammunition, having its primermix and propellant disc protected from the heat of the firing pin, by athermal seal.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes without the payment to us ofany royalty thereon.

The invention relates to a combustible primer plug for caselessammunition and more particularly to a combustible primer for caselessammunition having a thermal seal.

In the past, primer plugs have contained a primer mix and a propellantseal. This construction has proved operational when the caselesscartridge has been used in single-shot firings. But, when used in amachine gun, during automatic firing in long burst, the firing pinreached a temperature so high that the heat from said firing pin ignitedthe cartridge before it was properly seated in the chamber therebycausing malfunctioning of the machine gun.

The invention solves this problem by providing a mica thermal seal alongwith the propellant disc and primer mix in a primer plugv This micathermal seal prevents the heat from a hot firing pin from pre-ignitingthe primer.

It is therefore an object of the invention to provide a primer plug thatwill not be pre-ignited by a hot firing pin.

Another object of the invention is the provision of a caseless cartridgethat can be successfully fired from an automatic gun in long burst.

The above objects as well as others together with the benefits andadvantages of the invention will be apparent upon reference to thedetailed description set forth below, particularly when taken inconjunction with the drawing annexed hereto in which a primer plug isindicated generally by reference numeral 10. Said primer plug is madefrom molded propellant and fits in the rear portion "ice of a moldedcaseless cartridge (not shown). Said primer plug 10 has a pocket 12,located in the rearward portion thereof, which contains a primer mix 14.The function of the primer mix 14 is to initiate the combustible plug 10and then the caseless cartridge (not shown). After the primer mix 14 isinserted in the pocket 12, a propellant disc seal 16 is placed on top ofsaid primer mix 14 to hold it in place and to provide a combustiblematerial that will completely burn. A mica thermal seal 18 is thensecured on top of the propellant disc seal 16 thereby protecting samefrom a hot firing pin tip (not shown) during automatic firing in longburst. It has been found that, in a caseless machine gun, a burstgreater than sixteen rounds cannot be obtained without a mica thermalseal.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood, that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

We claim:

1. A combustible primer plug for caseless ammunition comprising a moldedpropellant, a pocket in said molded propellant, a primer mix secured insaid pocket for initiating said molded propellant, a combustible meansfor holding said primer mix in said pocket, and a thermal seal securedon top of said combustible means.

2. A combustible primer plug for caseless ammunition comprising a moldedpropellant, a pocket in said molded propellant, a primer mix secured insaid pocket for initiating said molded propellant, a combustible meansfor holding said primer mix in said pocket, and a mica thermal sealsecured on top of said combustible means.

3. A combustible primer plug for caseless ammunition comprising a moldedpropellant, a pocket in said molded propellant, a primer mix secured insaid pocket for initiating said molded propellant, a combustible discseal for holding said primer mix in said pocket, and a mica thermal sealsecured on top of said combustible disc seal.

Materials in Design Engineering, vol. 60, N0. 5, October 1964, p. 339.

SAMUEL FEINBERG, Primal Examiner.

ROBERT F. STAHL, Examiner.

1. A COMBUSTIBLE PRIMER PLUG FOR CASELESS AMMUNITION COMPRISING A MOLDEDPROPELLANT, A POCKET IN SAID MOLDED PROPELLANT, A PRIMER MIX SECURED INSAID POCKET FOR INITIATING SAID MOLDED PROPELLANT, A COMBUSTIBLE MEANSFOR HOLDING SAID PRIMER MIX IN SAID POCKET, AND A THERMAL SEAL SECUREDON TOP OF SAID COMBUSTIBLE MEANS.